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Add non-temporal note for maskmoveu_si128

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Like any other non-temporal instructions this has additional safety requirements
due to the mismatch with the Rust memory model. It is vital to know when using
this instruction.
This commit is contained in:
Aurelia Molzer
2025-07-24 14:41:07 +02:00
parent 0231fa9adf
commit be947d4d2b
1 changed files with 10 additions and 1 deletions
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11
library/stdarch/crates/core_arch/src/x86/sse2.rs
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@@ -1272,7 +1272,7 @@ pub unsafe fn _mm_loadu_si128(mem_addr: *const __m128i) -> __m128i {
}
/// Conditionally store 8-bit integer elements from `a` into memory using
/// `mask`.
/// `mask` flagged as non-temporal (unlikely to be used again soon).
///
/// Elements are not stored when the highest bit is not set in the
/// corresponding element.
@@ -1281,6 +1281,15 @@ pub unsafe fn _mm_loadu_si128(mem_addr: *const __m128i) -> __m128i {
/// to be aligned on any particular boundary.
///
/// [Intel's documentation](https://www.intel.com/content/www/us/en/docs/intrinsics-guide/index.html#text=_mm_maskmoveu_si128)
///
/// # Safety of non-temporal stores
///
/// After using this intrinsic, but before any other access to the memory that this intrinsic
/// mutates, a call to [`_mm_sfence`] must be performed by the thread that used the intrinsic. In
/// particular, functions that call this intrinsic should generally call `_mm_sfence` before they
/// return.
///
/// See [`_mm_sfence`] for details.
#[inline]
#[target_feature(enable = "sse2")]
#[cfg_attr(test, assert_instr(maskmovdqu))]